Printed circuit board

ABSTRACT

A printed circuit board comprised of a plurality of interconnected elements, wherein at least two elements to be connected of the printed circuit board are mechanically connected, particularly bonded or glued, with one another on at least one peripheral region thereof, while keeping a distance and being supported on a carrier element.

FIELD OF THE INVENTION

The present invention relates to a method for connecting a plurality ofelements of a printed circuit board, comprising the steps of

-   -   providing with mutually matching contours the elements to be        connected of a printed circuit board,    -   arranging with mutually complementary contours in a close        spatial relationship on at least one peripheral region the        elements to be connected, while keeping a distance between the        mutually facing peripheral regions, and    -   mechanically connecting, particularly bonding or gluing, the        mutually facing peripheral regions over at least portions        thereof, for connecting the elements to be connected of the        printed circuit board.

The invention relates furthermore to a printed circuit board comprisinga plurality of interconnected elements, as well as the use of suchmethod for the production of a multi-part circuit board.

PRIOR ART

In the context of the production of printed circuit boards, it is knownto produce a plurality of printed circuit boards or printed circuitboard elements on a common plate-shaped element, such printed circuitboards, as a rule, being each comprised of a plurality of conductive andinsulating layers and/or of components integrated in such a printedcircuit board. According to known production methods of this type, asubstantially full-surface assembly of a plurality of printed circuitboards on the common plate-shaped element is effected, whereupon, afterthe completion of the printed circuit boards, the latter are separatedfrom one another. In those cases, each of the printed circuit boards hasa respective edge region about its periphery, and hence outside asubstantially central region forming an actual printed circuit boardelement, in which the structures for the formation of the printedcircuit board and/or the electronic component are integrated. Said edgeregion is provided for carrying out further printed circuit boardprocessing steps, for instance, in the context of the insertion ofcomponents to be fixed to at least one surface and/or the installationinto an electric or electronic device, in order to enable themanipulation and, in particular, the automatic seizure of such a printedcircuit board during subsequent treatment or processing steps. Accordingto presently known process controls, it is thus to be anticipated thatthe peripheral region to be provided for the frame or the peripheralregion of the printed circuit board is likewise produced of a usuallyexpensive material in accordance with the usually multi-layered printedcircuit board. Such an edge or peripheral region, which is not requiredfor the functioning of the printed circuit board, will however, resultin elevated costs of such a printed circuit board, considering theusually multi-layered structure made of expensive materials. Inaddition, in the context of known production methods of printed circuitboards, regions or areas located between individual printed circuitboard elements, of the common plate-shaped element are discarded aswaste such that elevated costs for the production of printed circuitboards or printed circuit board elements will also occur in thisrespect.

In connection with the production of printed circuit boards it is,moreover, known to remove individual defective printed circuit boardsfrom a common plate-shaped element if they are recognized as defectivein the course of tests or checks, and to insert individual printedcircuit boards in place of such removed, defective printed circuitboards.

In addition, methods for collectively processing and handling printedcircuit boards are known, according to which several printed circuitboards or printed circuit board elements are usually inserted into frameelements each surrounding the printed circuit boards about their entireperipheries, and fixed to them, for instance, by bonding or gluing. Inthis respect, it is, for instance, referred to DE-A 1906 00 928, U.S.Pat. No. 4,689,103, U.S. Pat. No. 5,044,615, U.S. Pat. No. 5,866,852 orWO 2009/068741. Those known methods for inserting printed circuit boardsinto a frame element each completely surrounding the printed circuitboards, in particular, involve the drawbacks that the reception openingsto be provided in the frame element for the arrangement andpress-fitting of the printed circuit boards have to be precisely adaptedto the dimensions and shapes of the printed circuit boards to beinserted, while observing small manufacturing tolerances, and the properpositioning and fixation, for instance by bonding, on the peripheraledges of the printed circuit boards and frame elements, which usuallyhave comparatively small thicknesses, are therefore extremely difficultand complex.

It is, moreover, known to assemble individual printed circuit boards ofa plurality of elements produced, for instance, according to the aboveexposition, such elements having, for instance, been produced indifferent methods steps or production processes, as can, for example, betaken from US 2008/0144299 A1 or US 2009/0014205 A1.

For the simultaneous processing of printed circuit boards or printedcircuit board elements, it is further known to temporarily connectprinted circuit boards lying on a common transport path in a processingline, as can, for instance, be taken from WO 03/005785, wherein, afterthe completion of the processing of such several printed circuit boardelements arranged in a common transport plane, the separation of theinterconnected printed circuit boards or printed circuit board elementsis effected.

SUMMARY OF THE INVENTION

The invention aims to prevent or minimize the problems of knownconfigurations, particularly in the context of a precisely fittingconnection of several printed circuit board elements. The presentinvention, in particular, aims to provide a method, and a printedcircuit board, of the initially defined kind, in which the connection ofat least two elements to a common printed circuit board can be realizedin a simplified manner while avoiding tight and precise productiontolerances, favorably in a largely automated fashion.

To solve these objects, a method for connecting a plurality of elementsof a printed circuit board according to the kind mentioned-above issubstantially characterized in that the printed circuit board elementsto be connected are arranged or supported on a carrier element forcarrying out the connecting procedure, that the printed circuit boardelements to be connected are kept secured to the carrier element duringthe connecting procedure by applying a vacuum, by clamping, byelevations or pins projecting from the carrier element enteringcomplementary recesses of the elements, or the like and that the surfaceof the carrier element facing the elements to be supported is formed by,or coated with, an antiskid material, e.g. silicone, rubber or the like.

Due to the fact that, after having provided with mutually matchingcontours the printed circuit board elements to be connected, theelements to be connected are arranged while keeping a distance betweenthe mutually facing peripheral regions to be connected and aresubsequently mechanically connected, particularly bonded or glued, it isensured that a reliable connection of printed circuit board elements tobe connected will be achievable even when observing smaller productiontolerances, and hence by a simpler and quicker element production. Itwill, thus, for instance, also be possible to simply and reliablyprovide printed circuit board elements produced, or to be produced, indifferent methods steps with regard to the contours of peripheralregions to be connected, so that it will not be necessary to observe thetight and precise production tolerances essential for press fitting, asrequired in the initially mentioned embodiments according to the priorart. By keeping a distance, the appropriate space or clearance required,in particular, for the introduction of an adhesive will, moreover, beprovided, which, while again simplifying processing and connectingoperations, will ensure or enable a quicker connecting operation of suchprinted circuit board elements and, in particular, the automation ofsuch a connecting operation. For a reliable support of the elements tobe connected as well as for supporting an automation, it is proposedaccording to the invention that the printed circuit board elements to beconnected are arranged or supported on a carrier element for carryingout the connecting procedure. In order to secure the at least temporarypositioning of individual elements on the carrier element prior torealizing the final connection of elements to be connected, it isproposed according to the invention that the printed circuit boardelements to be connected are kept secured to the carrier element duringthe connecting procedure by applying a vacuum, by clamping, byelevations or pins projecting from the carrier element enteringcomplementary recesses of the elements, or the like. For the at leasttemporary securing or positioning on the carrier element, of the printedcircuit board elements to be connected, it is alternatively oradditionally proposed according to the invention that the surface of thecarrier element facing the elements to be supported is formed by, orcoated with, an antiskid material, e.g. silicone, rubber or the like.

Considering the usually small-dimensioned elements of a printed circuitboard as well as the production tolerances to be observed, which have tobe complied with even in the context of automated production processes,it is proposed according to a preferred embodiment that the distancebetween the mutually facing peripheral regions to be connected isselected to be 500 μm at most and, in particular, 200 μm at most. Bykeeping such a distance between the peripheral regions to be connected,it will be ensured that a reliable and relative positioning ofindividual such printed circuit board elements will be achievable evenin an automated fashion, such a distance being safely achievable andkeepable even when observing comparatively large production tolerances.In addition, the selection of such a distance proposed by the inventionwill also enable the quick and reliable introduction of, for instance,an adhesive into at least portions of peripheral regions to beconnected, of the elements to be connected. Furthermore, the keeping ofsuch a small distance proposed by the invention, between elements to beconnected will also permit the consideration of requirements in view ofa miniaturization of the printed circuit boards or printed circuit boardelements to be produced.

For the proper relative positioning of elements to be connected, it isproposed according to a further preferred embodiment that elements to beconnected are arranged and connected with reference to at least onealigning or registering element provided on one of the elements to beconnected. Such an aligning or registering element can, for instance, beformed by an opening or passage provided on at least one of the elementsto be connected. When treating or processing a plurality of printedcircuit boards each optionally comprised of several elements, it is,moreover, known to provide an appropriate plurality of aligning orpositioning elements for such plate-shaped or panel-shaped arrays ofseveral printed circuit boards, in order to enable the reliablepositioning of a plurality of elements.

For the reliable and rapid connection of printed circuit board elementsto be connected, it is, moreover, proposed that a thermally orchemically or UV or IR curable adhesive is used for bonding, as incorrespondence with a further preferred embodiment of the methodaccording to the invention.

Considering the elements of a printed circuit board and, in particular,insulating or plastic layers of such a, particularly multilayer, printedcircuit board, which, as a function of the selected materials, must notbe subjected to extremely high temperatures during subsequent processingsteps, it is proposed according to a further preferred embodiment thatthermal curing of the adhesive is carried out at temperatures between80° C. and 300° C.

In order to achieve a reliable and targeted arrangement of the adhesiveused for connecting the elements to be connected, it is proposedaccording to a further preferred embodiment that a high-viscosityadhesive is used. Such a high-viscosity adhesive can be appropriatelyintroduced into the distances or clearances between the printed circuitboard elements to be connected while, in particular, preventing flowingor excessive spreading in the region of the distances, even when takinginto account the comparatively small distances of the elements to beconnected.

For a particularly reliable application or arrangement of the adhesivein the distances of elements to be connected, it is, moreover, proposedthat the adhesive is applied by the aid of a dispensing device ordispenser, template printing, screen printing or the like, as incorrespondence with a further preferred embodiment of the methodaccording to the invention.

In order to avoid spreading of the adhesive, particularly below elementsto be connected, it is proposed according to a further preferredembodiment that the adhesive is merely introduced or arranged over aportion of the vertical extension of side edges of the peripheralregions to be connected. Particularly by selecting the appropriateviscosity of an adhesive and whilst taking into account thecomparatively small distance between adjacent peripheral regions to beconnected, of the elements to be connected, the adhesive will be safelyprevented from filling-up and penetrating over the entire verticalextension of the gap or distance between elements to be connected.

For a, particularly temporary, positioning, for instance in the presenceof a plurality of elements to be connected, wherein curing of theadhesive is, for instance, carried out after the arrangement of aplurality of such elements, it is proposed according to a furtherpreferred embodiment that a temporary connection of peripheral regionsto be connected is formed by using a removable adhesive tape or label.Such removable adhesive tapes or labels can be easily and reliablypositioned and even after the arrangement of elements to be connectedwill additionally permit at least minor corrections of the respectivemutual positions prior to realizing the final connection.

Particularly when using a carrier layer or carrier element, it isproposed, in order to avoid adherence during the introduction of anadhesive, particularly at an inadvertent passage of the adhesive throughthe entire clearance between the mutually facing peripheral regions,that a removable protective element, for instance a removable sheet ofpaper, is arranged below the peripheral regions to be connected, of theelements to be connected, as in correspondence with a further preferredembodiment of the method according to the invention. Such a protectiveelement and, in particular, removable sheet of paper can be readily andreliably arranged at least in areas where peripheral regions to beconnected are arranged during the connecting procedure, and can again bereadily removed from the printed circuit board elements connected withone another upon completion of the connection.

By providing a distance between printed circuit board elements to beconnected, which will not only be advantageous in view of the automatedpositioning of individual elements to be connected but also enable thesimplified production of the same, an optionally required separation ofelements to be connected or already connected may also be effected alongthe distance to be kept between the same. In this context, it isproposed according to a further preferred embodiment that connectedelements of a printed circuit board can be separated along theinterconnected peripheral regions, e.g. for repair purposes,particularly by using a cutter or laser. In this manner, expensiveelements of a printed circuit board can thus, for instance, be removedfrom such a printed circuit board in case of damage and replaced withnew elements, so that a printed circuit board need not be completelyexchanged at a locatable damage of merely a portion thereof.

While substantially linear peripheral regions of printed circuit boardelements to be connected can be reliably connected by the mechanicalconnection, particularly bonding, provided by the invention, it isproposed according to a further preferred embodiment, particularly forenabling the mutual engagement of portions of the peripheries to beconnected, of individual elements, that elements to be connected in amanner known per se are each formed with at least one relativelycomplementary coupling element on peripheral regions to be connected.Such complementary coupling elements can likewise be produced in asimplified manner with accordingly large production tolerances whiletaking into account the distances to be kept between elements to beconnected, and likewise allow for the substantially automated fitting-inof elements to be connected, said complementary coupling elementsfacilitating positioning and enhancing the mechanical strength of theconnection.

In this context, it is proposed according to a further preferredembodiment that the at least one coupling element of an element to beconnected is formed by a profiled coupling element projecting from theperipheral region of said element and received in a complementary recessof the element to be connected therewith, while keeping said distance.By providing appropriate coupling elements, the mechanical stability ofthe connection of the elements to be connected will thus, in particular,be further improved or enhanced.

Particularly when arranging or providing frame or carrier elements forreceiving or holding elements of a printed circuit board which are, forinstance, made of more cost-effective materials and can be used fortreating or processing purposes, it is proposed according to a furtherpreferred embodiment that a substantially rectangular element of aprinted circuit board, on respectively opposite peripheral regions, iseach provided with at least one coupling element each connected with acoupling element of a frame or carrier element cooperating therewith.

As already pointed out above, it is possible to produce several elementsto be used for the production of a printed circuit board and to beconnected with one another, in, for instance, different production stepsand at, for instance, different construction expenditures, so that itis, moreover, preferably proposed according to the invention that aplurality of elements of a printed circuit board are connected with oneanother in a spaced-apart relationship.

To solve the initially mentioned objects, a printed circuit boardcomprised of a plurality of interconnected elements is essentiallycharacterized in that at least two elements to be connected of theprinted circuit board are mechanically connected, particularly bonded orglued, with one another on at least one peripheral region thereof whilekeeping a distance and being supported on a carrier element. As pointedout above, an automation of the production of such printed circuitboards comprised of at least two elements will also be feasible in afavorable manner whilst observing accordingly large productiontolerances for the elements to be connected.

For a proper mechanical connection in compliance with the requirements,for instance with regard to a miniaturization of such printed circuitboards, it is, moreover, proposed in a preferred manner that thedistance between the mutually facing peripheral regions to be connectedis selected to be 500 μm at most and, in particular, 200 μm at most.

For the proper mutual positioning of individual elements to beconnected, it is, moreover, proposed that elements to be connected arearranged, and connected with one another, with reference to at least onealigning or registering element provided on one of the elements to beconnected, as in correspondence with a further preferred embodiment ofthe printed circuit board according to the invention.

For a reliable and simple connection, it is, moreover, proposed in apreferred manner that a thermally or chemically or UV or IR curableadhesive is used for bonding, adhesives curing in such a manner beingknown per se in the context of the production of printed circuit boards.

For a reliable connection, it is, moreover, proposed that the adhesiveis merely introduced or arranged over a portion of the verticalextension of side edges of the peripheral regions to be connected, as incorrespondence with a further preferred embodiment of the printedcircuit board according to the invention.

For an optionally required separation, particularly upon detection of adamage of a portion of the printed circuit board according to theinvention, it is, moreover, proposed that connected elements of aprinted circuit board are separable along the interconnected peripheralregions, e.g. for repair purposes, particularly by using a cutter orlaser, as in correspondence with a further preferred embodiment of theinvention.

For the simple positioning and mechanically stable coupling orconnection of elements to be connected, it is, moreover, proposed in apreferred manner that elements to be connected, in a manner known perse, are each formed with at least one relatively complementary couplingelement on peripheral regions to be connected, wherein, in this context,it is proposed according to a further preferred embodiment that the atleast one coupling element of an element to be connected is formed by aprofiled coupling element projecting from the peripheral region of saidelement and received in a complementary recess of the element to beconnected therewith, while keeping said distance.

In addition, the use of the method according to the invention for theproduction of a multi-part circuit board is proposed.

SHORT DESCRIPTION OF THE DRAWINGS

In the following, the invention will be explained in more detail by wayof exemplary embodiments schematically illustrated in the drawing.Therein:

FIG. 1 illustrates schematic top views on different embodiments ofconnected elements of a printed circuit board, using the methodaccording to the invention, an element of a printed circuit boardpartially encompassing a further element in FIG. 1 a, a printed circuitboard element being completely encompassed by a further element in theembodiment according to FIG. 1 b, several printed circuit board elementsbeing encompassed or surrounded by a common element in the embodimentaccording to FIG. 1 c, and several printed circuit board elements beingconnected with one frame or carrier element each on respectivelyopposite edges in the embodiment according to FIG. 1 d;

FIG. 2 on an enlarged scale depicts schematic views of differentconfigurations of coupling elements between printed circuit boardelements to be connected;

FIG. 3 schematically illustrates the course of procedure of connectingprinted circuit board elements to be connected, FIG. 3 a depicting theside-by-side arrangement of elements to be connected, FIG. 3 b depictingthe application of an adhesive for connecting the elements to beconnected; and FIG. 3 c depicting the state after having applied theadhesive;

FIG. 4 is a schematic top view on the relative arrangement of aplurality of elements of a printed circuit board relative to one anotherwith reference to at least one aligning or registering element;

FIG. 5 is a schematic top view of a carrier element for arranging aplurality of printed circuit board elements to be connected, with anegative pressure or vacuum being generated and applied for temporaryfixation;

FIG. 6 is a schematic illustration of a modified embodiment of thearrangement of a plurality of elements on a carrier element, FIG. 6 adepicting a schematic partial section and FIG. 6 b being a schematic topview;

FIG. 7 is a schematic view of a configuration of a temporary fixation oftwo elements to be connected, using an adhesive tape; and

FIG. 8 schematically illustrates the course of procedure of connectingand subsequently separating two elements, for instance for repairpurposes and for an exchange of one of such interconnected elements.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

In respect of the Figures, it is initially noted that in some cases onlyportions of elements of a printed circuit board to be produced are shownin the region of fixation of elements to be fixed to one another orconnected with one another. Furthermore, the relative dimensions,particularly in regard to a distance to be provided between theindividual elements, are not illustrated true to scale. Moreover, for asimplified illustration, no patterning is indicated and no componentsoptionally attached or to be received are illustrated on the individualelements of a printed circuit board to be produced.

In the illustration according to FIG. 1, different options forconnecting printed circuit board elements to be connected areschematically indicated, the indicated options merely showing exemplaryembodiments not to be interpreted in a limiting sense.

In the embodiment according to FIG. 1 a, a substantially rectangular orsquare element 1, on two peripheral sides, is surrounded by an element 2to be connected therewith as will be discussed in more detail below, adistance or gap 3 being indicated between the elements 1 and 2 to beconnected with each other. Mutually facing peripheral regions of theelements 1 and 2 are denoted by 28 and 29, respectively.

In the embodiment according to FIG. 1 b, an again substantially squareelement 1 is surrounded by a likewise substantially square element 4,the square element 1 being, for instance, taken up on substantially allperipheral sides while substantially again keeping a distance or gap 3.

In the embodiment according to FIG. 1 c, a plurality of elements againschematically indicated by 1 are received in a common element 5, adistance or gap 3 being again provided between the individual elements1.

The different elements 1, 2, 4 and 5 of a printed circuit board, whichare illustrated in FIGS. 1 a to 1 c, can, for instance, be produced bydifferent production methods of a particularly multilayer printedcircuit board and, upon completion of the same, can be connected orcoupled with each other for providing a finished printed circuit boardcomprising different portions or elements, as will be discussed in moredetail below.

In the embodiment according to FIG. 1 d, it is indicated that aplurality of elements 6, on respectively opposite peripheral regions orside edges 7, are each provided with coupling elements schematicallydenoted by 8, said coupling elements 8 cooperating, or being connected,with complementary coupling elements 9 provided on frame or carrierelements 10. It is apparent, also from the embodiment according to FIG.1 d, that a distance or gap 3 is each provided or maintained in theregions of the coupling elements 8 and 9 as well as the adjoiningperipheral regions 7 of the elements 6 and the peripheral regions 11 ofthe frame elements 10.

FIG. 2 schematically depicts different embodiments of coupling elements,which, irrespective of their geometric shapes, are again denoted by 8for the sake of simplicity, which cooperate with complementary recesses9. As is apparent from the illustration according to FIG. 2, a distanceor gap 3 is each again provided in the region of the mutuallycooperating coupling elements 8 and 9.

While, in the illustration according to FIG. 1, coupling elements 8 and9 are merely indicated in the embodiment according to FIG. 1 d, itshould be noted that such coupling elements 8 and 9 of elements to beconnected, as are, for instance, indicated in FIG. 2 may also be used onthe respective peripheral regions 28 and 29 in the embodimentsillustrated in FIGS. 1 a to 1 c.

Moreover, the embodiments of coupling elements 8 and complementaryrecesses 9 illustrated in FIG. 2 are merely exemplary and not to beinterpreted in a limiting sense.

A connection procedure of two elements to be connected will be discussedin more detail below with reference to the illustration of FIG. 3,wherein, for instance, for a configuration as illustrated in FIG. 1 dusing coupling elements 8 and 9 according to FIG. 2 a, only portions ofthe elements to be connected are each shown in FIG. 3. In FIGS. 3 a, 3 band 3 c, a schematic top view on such a portion of a connection ofmutually cooperating coupling elements 8 and recesses 9 is, furthermore,each indicated on the left-hand sides of the illustrations, whilesections along lines A-A, B-B and C-C are additionally indicated for theindividual method steps on the right-hand sides of the illustrations.

From the method step illustrated in FIG. 3 a, it is apparent thatelements to be connected, which are again denoted by 6 and 10 as incorrespondence with the illustration according to FIG. 1 d, in theregion of their mutually complementary coupling elements are positionedrelative to each other in such a manner as to each keep a distance 3substantially over the entire periphery of the coupling elements 8 and 9as well as in the region of the mutually facing peripheral regions 7 and11 for the subsequent introduction of an adhesive.

The distance 3 is chosen to have a maximum width of 500 μm, favorably200 μm, so as to allow the elements to be connected, which areoptionally provided with additional coupling elements 8 and 9, to beproduced with large production tolerances. The maintenance of such adistance of, for instance, 200 μm at most, moreover, also allows for thearrangement of a plurality of elements optionally forming a plurality ofprinted circuit boards on a common carrier element to be used forfurther processing, e.g. for inserting components, as will be discussedin more detail particularly with reference to FIG. 4, wherein relativeorientation tolerances between such a plurality of elements to bearranged, of ±50 μm, in particular ±30 μm, are attainable or can beobserved. By providing a maximum distance of 200 μm for the subsequentintroduction of an adhesive, the automated assembly and connection ofprinted circuit board elements to be connected in this manner will befeasible such that cumbersome fitting procedures of elements, whichwill, in particular, have to be performed manually, can be obviated.

After having arranged in a spatially close relationship the elements tobe connected, as is illustrated in FIG. 3 a, the application of anadhesive 12 is, for instance, effected in the method step according toFIG. 3 b by the aid of a doctor blade 13 using a template 14 such that,after having applied the adhesive 12 and removed the template 14, as isillustrated in the method step according to FIG. 3 c, the adhesive 12was introduced into the gap 13 for connecting the elements 6 and 10 tobe connected.

As is apparent from the illustration according to FIG. 3 c, the adhesive12, which has a high viscosity, in a favorable manner is merelyintroduced over a portion of the vertical extension of the gap 3 so asto avoid a penetration of the adhesive 12 to the lower side of theelements 6 and 10, and hence the adherence of the elements to a carrierelements, particularly when supporting the elements 6 and 10 to beconnected, as will be discussed in more detail with reference to FIG. 5.It is further apparent from the illustration according to FIG. 3 c that,in particular as a function of the thickness of the template 14employed, the adhesive 12 only slightly projects beyond the surfaces ofthe elements 6 and 10 such that, in particular, subsequent processingsteps will not be impaired or affected.

The application of the adhesive as indicated in FIG. 3 c is, forinstance, followed by the curing of the same, using heat or UV light.When using a thermally curing or setting adhesive 12, temperaturesbetween 80° C. and 200° C. are, for instance, selected in order toparticularly avoid impairment to the already finished printed circuitboard elements.

To simplify subsequent method steps, an adaptation of the expansioncoefficient of the adhesive 12 to that of the adjoining elements 6 and10, respectively, is moreover effected.

Instead of using the template printing process indicated in FIG. 3 c,the adhesive 12 may, for instance, be applied by screen printing or bydispensing in the zones of the mutually facing peripheral regions 7 and11 of the elements 6 and 10 to be connected.

From the illustration according to FIG. 3, it is, moreover, apparentthat an arrangement of the adhesive 12, and hence a mechanicalconnection between the elements to be connected, is merely provided inthe region of the coupling elements 8 and 9. Alternatively, asubstantially full-area connection over the entire peripheral regions 7and 11 of the elements 6 and 10 to be connected may be provided in orderto, in particular, increase the strength of the connection of theelements 6 and 10 to be connected.

Such a method, particularly when increasing or improving the strength ofa connection between adjacent elements 6 and 10 by supporting thecoupling elements 8 and 9 will, for instance, enable the provision of aload-carrying capacity of, for instance, 2 kg, which will be sufficientfor the further use or processing of such printed circuit boards. Itwill, moreover, also be ensured that no changes of the mechanicalconnection produced between the elements 6 and 10 to be connected willoccur, for instance, in subsequent treatment or processing steps suchas, e.g., reflow or soldering processes, for instance for fixingcomponents.

FIG. 4 schematically indicates that, when positioning a plurality ofelements 15 in a common element 16, particularly by departing from analigning or registering element 17 formed, for instance, by a bore orpassage, while keeping a respective maximum distance 3 of, for instance,200 μm, the alignment of such neighboring elements 15 will be achievablewith reference to aligning elements 18 and 19 additionally provided onthe individual elements 15, while observing a tolerance of ±50 μm, inparticular ±30 μm. The observance of such small tolerances of a relativealignment is especially necessary or beneficial for subsequent treatmentor processing procedures such as the insertion of components, in orderto fix components not illustrated in detail on such elements 15 in alikewise particularly automated fashion.

From the schematic illustration according to FIG. 5, it is apparent thata plurality of elements to be each connected with one another, which areagain denoted by 6 and 10 as in correspondence with the embodiment ofFIG. 1 d, are arranged on a carrier element schematically indicated by20, which is formed with a plurality of openings or passages 21 forgenerating or applying a negative pressure or vacuum from a vacuumsource not illustrated in detail.

In order to prevent the penetration of an adhesive in the region of theconnection of the elements to be connected, and hence an adherence tothe carrier element 20, it is, moreover, indicated in FIG. 5 that aprotective layer, for instance a removable paper sheet 22, is arrangedin the region of the bonding sites, which protective layer can be easilyremoved again after having connected the elements 6 and 10 to beconnected, even after a penetration of the adhesive over the entirevertical extension of the peripheral regions to be connected, thuspreventing the adherence to the carrier element 20 and, in particular,the contamination of the same by the adhesive.

In the embodiment according to FIG. 6, a carrier element is denoted by30, wherein elevations or pins 31 project from the carrier element 30,which, through openings or passages schematically indicated at 32, enteran element again denoted by 6 for at least temporarily securing elementsto be connected with one another. With the element 6, which istemporarily secured to the carrier element 30 by the pins or elevations31 cooperating with the openings 32, are subsequently connected elementsagain denoted by 10, in particular frame or carrier elements, which,also via pins again schematically indicated by 31, are secured on thecarrier element 30 in their respective positions relative to the element6 to be connected therewith, which has been omitted from FIG. 6 b forthe sake of clarity. An aligning or registering element again denoted by17 is indicated for positioning or aligning.

In the same manner as described in respect to the preceding embodiments,an adhesive is again introduced into the gap 3 between the elements 6and 10 for connecting elements 6 and 10.

In the illustration according to FIG. 6, the coupling elements whichare, for instance, additionally provided in preceding Figures forconnecting elements 6 and 10 are, moreover, not illustrated and can beomitted.

Instead of, and/or in addition to, holding or securing the elements tobe connected by applying a vacuum as illustrated in FIG. 5 as well as bythe positioning pins 31 and the respective openings or passages 32 forreceiving the same as in accordance with FIG. 6, temporary securement onthe carrier element 20 or 30 can, for instance, also be provided byclamping the individual elements to the carrier element until theapplication and, in particular, curing of the adhesive to be introducedinto the distance or gap 3 between elements 6 and 10 to be connected hasbeen completed.

In addition, or as an alternative, the surface of the carrier element 20and/or 30 facing the elements 6 and 10 to be connected may be formed byan antiskid material such as silicone, rubber or the like, or coatedwith such material, in order to secure the relative positioning of theelements 6 and 10 to be connected. In this manner, an at leasttemporarily secured positioning of the elements 6 and 10 to be connectedwill be ensured, in particular, without additionally providing theapplication of a vacuum as indicated in FIG. 5 or using additionalpositioning pins 31 and respective recesses or passages 32 as indicatedin FIG. 6.

In the illustration according to FIG. 7, it is schematically indicatedthat elements to be connected, which are again denoted by 6 and 10, aretemporarily secured to each other by an adhesive tape or adhesive label23, said adhesive tape 23 being removable again upon connection of theelements 6 and 10.

The distance or gap 3 provided between printed circuit board elements tobe connected, which not only renders feasible the simplified productionas well as the automated assembly and connection of the same, alsoenables, for instance, defective printed circuit board elements and, ifnecessary, printed circuit board elements loaded with expensivecomponents to be separated again, particularly along the connection siteor line, and, in particular, expensive elements of a printed circuitboard to be replaced accordingly.

FIG. 8 schematically indicates such an exchange or repair process.

Departing from two printed circuit board elements I and II according toFIG. 8 a, which are connected with each other according to FIG. 8 b asis, for instance, illustrated in more detail in FIG. 3, the method stepaccording to FIG. 8 c comprises the separation of the interconnectedprinted circuit board elements I and II along the connection site 25using, for instance, a cutter or laser.

After a separation along the coupling elements 8 and 9 as illustrated inFIG. 8 c, the defective element II can be detached from element I asindicated by arrow 26 in FIG. 8 d, whereupon a new element III isinserted in the sense of arrow 27 in FIG. 8 e and connected with elementI by a bond or glued connection again denoted by 12.

Thus, printed circuit board elements which are simple to produce withlarge processing tolerances can be safely and reliably connected withone another at reduced operating expenditures and, in particular, withthe option of automated arranging and connecting procedures.

1. A printed circuit board comprised of a plurality of interconnectedelements, wherein at least two elements to be connected of the printedcircuit board are mechanically connected, particularly bonded or glued,with one another on at least one peripheral region thereof, whilekeeping a distance and being supported on a carrier element.
 2. Theprinted circuit board according to claim 1, wherein the distance betweenthe mutually facing peripheral regions to be connected is selected to be500 μm at most and, in particular, 200 μm at most.
 3. The printedcircuit board according to claim 1, wherein elements to be connected arearranged, and connected with one another, with reference to at least onealigning or registering element provided on one of the elements to beconnected.
 4. The printed circuit board according to claim 1, wherein athermally or chemically or UV or IR curable adhesive is used forbonding.
 5. The printed circuit board according to claim 4, wherein theadhesive is merely introduced or arranged over a portion of the verticalextension of side edges of the peripheral regions to be connected. 6.The printed circuit board according to claim 1, wherein connectedelements of a printed circuit board are separable along theinterconnected peripheral regions, e.g. for repair purposes,particularly by using a cutter or laser.
 7. The printed circuit boardaccording to claim 1, wherein elements to be connected, in a mannerknown per se, are each formed with at least one relatively complementarycoupling element on peripheral regions to be connected.
 8. The printedcircuit board according to claim 7, wherein the at least one couplingelement of an element to be connected is formed by a profiled couplingelement projecting from the peripheral region of said element andreceived in a complementary recess of the element to be connectedtherewith, while keeping said distance.